1. Field of the Invention
The present invention relates generally to a channel estimation method and apparatus in an Orthogonal Frequency Division Multiplexing (OFDM) wireless communication system, and in particular, to a method and apparatus for realizing a channel estimation algorithm based on a block-type training sequence.
2. Description of the Related Art
Generally, channel estimation is achieved based on a training sequence. The training sequence has a block-type structure. Such a training sequence is equal in structure to the training sequence proposed in the IEEE 802.11 standard.
There is a Least-Square (LS) algorithm as a simple channel estimation algorithm. Actually, the LS algorithm is very popularly used. A Minimum Mean-Square Error (MMSE) algorithm is a channel estimation algorithm advanced from the LS algorithm in terms of the performance. However, the MMSE algorithm is higher in complexity than the LS algorithm.
The two channel estimation algorithms have the following characteristics.                LS algorithm: This algorithm is very low in the complexity, but has poor Packet Error Rate (PER) performance at a low Signal-to-Noise Ratio (SNR).        MMSE algorithm: This algorithm is very high in the complexity, but has good PER performance at a low SNR.        
As described above, in the channel estimation algorithms, there is a trade-off relationship between the complexity and the performance. That is, the reduction in the complexity causes the decrease in the performance, and the increase in the performance causes the increase in the complexity.
Therefore, constant research is being conducted on a channel estimation algorithm capable of providing good performance with the low complexity, but it is very hard to realize the algorithm.